Electrical treating apparatus, especially for sterilization



Oct. 11, 1938. F s, TH 2,132,707

ELECTRICAL TREATING APPARATUS, ESPECIALLY FOR STERILIZATI ON Filed Oct. 8. 1934 5 Sheets-Sheet l ATTORNEYS F. 8. SMITH Oct. 11,1938.

ELECTRICAL TREATING APPARATUS. ESPECIALLY FOR STERILIZATION Filed 001;. 8, 1934 5 Sheets-Sheet 2 INVENTOR. FfiF/V/(A //v 5. 577/771 ATTORNEYS Oct. 11, 1938. MITH 2,132,707

ELECTRICAL TREATING APPARATUS, ESPECIALLY FOR STERILIZATION Filed Oct. 8, 1934 5 Sheets-Sheet 5 ATTORNEY5 Oct. 11, 1938.

ELECTRICAL Filed Oct. 8, 1934 5 Sheets-Sheet 4 ATTORNEYS Oct. 11, 1938. F 8. SMITH 2,132,707

ELECTRICAL TREATING APPARATUS, ESPECIALLY FOR STERILIZATION Filed 001;. 8, 1934 5 Sheets-Sheet 5 INVENTORL Fii/v/Q //v 5. 5/1/76 A TTORNEYS Patented Oct. 11, 1938 PATENT ()FFICE ELECTRICAL TREATING APPARATUS, ESPE- CIALLY FOR STERILIZATION Franklin S. Smith, New Haven, Conn. Application bctober 8, 1934, Serial No. 747,441

50 Claims.

This invention relates to the treatment of materials and especially to the electrical sterilization of particularly food products and more particularly to the destruction electrically of insect life, such as the pupae, larvae, eggs, and the like, therein.

One of the objects of this invention is to provide an efficient and dependable apparatus which is particularly adapted for achieving the electrical sterilization of products, such as cereals, flour, and the like, and for effectively destroying therein such insect life as such products are frequently infestedwith, taking the form usually of eggs, larvae, pupae, and the like. Another object is to provide an apparatus of the abovementioned character in which, in particular, packaged products may be dependably treated or sterilized and in which, moreover, the efifects of the dielectrics constituting the cartons or packages, tending in certain physical relations to oppose uniform sterilization of the contents, may be effectively and, moreover, in a simple and dependable manner, overcome. Another object isto provide an apparatus of the above-mentioned character a simpler and less expensive, but nevertheless efficiently acting, electrode construction and, moreover, one that will be well adapted to ready and quick replacement, capable of substantially entirely avoiding the effects of air currents or rarefactions of air, due to the movement of the electrode, and capable, also, of rapid and inexpensive manufacture. Another object is to provide an electrode construction that will be well adapted for long-continued use and in which also efiicient and simple cooling action may be dependably achieved.

Another object is to provide, in an apparatus of the above-mentioned character, a conveyor means or system better adapted particularly to the handling of bulky packages or cartons and adapted, furthermore, to take part in a unique, simple, and thoroughly practical way, in the achievement of the desired electrical sterilizing action. An-' tions of practical use. Other objects will be ir part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements,

and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of the various possible embodiments Figure 3 is a transverse vertical sectional view,

certain parts being omitted, as seen along the 2 line 3-3 of Figure 2;

Figure 4 is a vertical sectional view, as seen along the line 4-4 of Figure 1-, certain parts being omitted;

Figure 5 is a front elevation-of a double electrode mounting and drives therefor, on an en- 'larged scale, one of the electrodes and its drive being shown in central vertical cross-section;

Figure 6 is a side elevation, as seen along the line 66 of Figure 5, of one of the electrodes and 3 its drive,

Figure 7 is a diagrammatic representation of the relation of one electrode, to the packaged product and itsaction thereon;

Figure 8 is a view like that of Figure '7 but showing the reversed action =on the packaged product of another or a companion electrode.

Similar reference characters refer to similar parts throughout the several views in the drawings.

Referring now first to Figures 1 and 2, I have there shown a casing or housing, generally indicated at H], within which certain parts of my apparatus are enclosed and by which certain other parts may be supported, the housing being preferably built up of sheet metal and a suitable framework and being in general not unlike that disclosed in my co-pending application Serial No.

627,291, filed August 2, 1932, issued October 9,

1934, as Patent No. 1,975,805, to which reference may be made for further details. In the righthand wall Ill of the housing I0 is provided a. suitable aperture through which and onto a suitable chute or slide II the products to be sterilized usuallyor illustratively packaged food products, may be'injected onto a conveyor means, to

'be more clearly described hereinafter, and compropriately related to the left-hand end of the conveyor means A, B, C and to a suitable opening in the left-hand end wall III of the housing I0. 1

, The conveyor means A, B, C is appropriately supported within the housing Ill, preferably resting upon and suitably secured tothe bottom I of the housing I0 and it extends, as will now be clear, from one end wall I 0*- to the other end wall lt It includes certain driven roller members, the roller members of sections A and C being preferably of identical construction whereas the roller members of the central or intermediate section B, falling within the sterilizing or treatment 'zone or zones, as will be presently made clearer, are of identical construction but different from the construction of the rollers of the sections A and C, being also of greater length transversely of the apparatus (see Figure 2) than are the rollers of sections A and C of the conveyor. The rear ends of all of the rollers, however, are preferably alined and find support in the same side frame structure. 1

Accordingly, I providea side frame structure or beam I3 (Figure 1, 2, 3 and 4), the member I3 being preferably made of solid dielectric material, such as laminated bakelite, or the like, and being preferably of unitary construction throughout its length thereof, of course, it may be built up in any suitable or appropriate manner; at its right-hand end (Figure 1) it is provided with a downward extension I3, forming a sort of leg which is bolted or otherwise secured to a suitable upright-or standard I I secured to the right-hand end of the bottom or floor Ill of the housing I 0, and at its left-hand end (Figure 1) it is likewise provided with a downward extension or leg portion I3 which is bolted or otherwise secured to the standard I5 which, like the standard I l, rests upon and is secured to the .fioor III of the housing I0 and extends crosswise of the -latter.

At closely spaced intervals along the uppermost longitudinal and horizontally extending edge of i the side frame or beam I3, the latter supports or has suitably secured thereto a series of bearings I6, preferably of the so-called oil-less type made, for example, of oil-impregnated wood. As is better shown in Figures 3 and 4, this upper edge of the beam I3 maybe recessed for each bearing I6 which may be set into sucha recess and secured in place in any suitable way. a Illustratively I may provide, for section A, twelve such bearings I6, for section Ed the conveyor means I may provide sixteen such bearings I6, and for section C, generally similar in construction to section A, I may likewise provide twelve such bearings IE, it being now clear that the side frame or beam I3 is common to and extends throughout all of the three conveyor sections A, B and C.

Laterally juxtaposed to that portion of the frame I3 that extends throughout section A (see Figures'l and 2) I provide a side frame or cantilever-like member I'I, also'made preferably of solid dielectric material, such as laminated bakelite, and provided at itsu ight-hand portion with a downwardly directed extension or leg I'I which is secured as by bolts or screws to the other side face of the standard It, member I'I being thereby positioned in parallelism to the side frame I3 and with its upper edge alined with the upper edge of the member IS. The upper edge of the side-frame member I! is provided, at simi-' larly spaced intervals, and in a similar manner, as the A-portion of the side frame I3 with bearings I8 (see Figures 1, 2 and 4) of a. construction substantially. like the bearings I 6 above described, and in the thus juxtaposed or paired bearings I 6 and I8, throughout thesection A, I rotatably mount rollers I9, illustratively twelve in number, as' above noted, rollers I9 being of a construction better shown in Figure 4.

The rollers I 9 are made preferably of any suitable solid dielectric material; they may, for example, be made of .bakelite or even of a material like glass,- and they are provided with stud shafts I9 and I9 receivable respectively in the bearings I6 and I8 (Figure 4), being thereby mounted for free rotation. As is better shown in Figures 2 and 4, the rollers are closely spaced, and are parallel to each other, forming a supporting or conveying surface alined with the entry chute II (Figure 1) and when driven in counter-clockwise direction, as viewed in Figure 1, act to move the products or articles presented thereto from the chute II, in a directio toward the left. The rollers I9 are driven in a ganner more clearly hereinafter described, it bein sufficient at this point to note that, referring to Figures 4 and 2, the rollers I9 are provided at the ends thereof nearest the side frame member I 8 with'a belt-receiving groove I9.

The rollers I9 of section A are thus effective to bring the product or packages or articles to be sterilized to the section B which, as above noted. is in the treatment zone or zones and forms a part thereof, as will be more clearly presently described, while the products, packages, or articles, having emerged from the treatmentsection B in their movement toward the left. (Figures 1 and 2) are carried away from section B and discharged onto the discharge chute IZ (Figure 1) by rollers (Figure 2) which are illustratively twelve in number, as earlier noted, and which, moreover, are of a construction identical to that of rollers I9 above described in detail; at one end thereof they are rotatably supported in the bearings I6 of the C-portion of the side frame I3 and at thein opposite ends they are supported in bearings 2|, identical to the bearings I6 or II! rollers I9 of section A, are provided at the ends thereof nearest the side beam I3 with belt-receiving grooves 20 in orderthat they may be driven as later described in detail, in counter-clockwise direction, as viewed in Figure 1, and thereby effect movement of the product or packages toward the left, to be discharged from the apparatus.

Since there are effective in the treatment zone of section B certain high potentials, all as later described, the shapes and dimensions of the side frame I3 and of the side frame members I1 and 22, will be seen-to provide relatively -very long paths from the intermediate or treatment zone section B to the otherwise grounded and metallic standards It and I5 (Figure 1), and thereby negative the loss of energy, as by leakage to ground,

from the treatment zone B, and it is particularly for a similar reason that the rollers I9 and 20 are preferably made of solid dielectric material.

In the treatment or intermediate section B of' the construction, I provide roller-like members 23 (Figure 2) and they are constructed preferably as is better shown in Figure 3, being, as already earlier noted, illustratively sixteen in number, and being of greater axial length than the rollers l9 and 20 (see Figure 2). Members 23 (see now Figure 3) are made of solid dielectric material, preferably, however, of glass, pyrex glass, or quartz, by way of illustration, and particularly where made of glass, being, for reasons later described, made in the form of tubing, are relatively thick-walled, as is indicated in Figure 3. At-

their rear ends, as viewed in Figure l, or at their left-hand ends, as viewed in Figure 3, the glass tube members 23 may be closed and provided with a stud-like extension 23 supported in the bearings 16 above describedand which extend throughout the B-portion (Figure 2) of the side frame or beam 13, and adjacent the bearing'portion 23 thereof, the glass tube members 23 are provided each with a belt-receiving'groove 23", it being thus noted that all of the rotary members I9, 23 and 20 thus have their respective beltreceiving. grooves I9, 23 and 2|! all alined (see Figure 2) adjacent to and lengthwise of the common side frame member l3. Moreover, it will be seen (Figure 2) that the rotary members 23 of section B are also closely spaced and that allof the rotary members are preferably of the same outside diameter; when members 23 .are rotatedin counter-clockwise direction, as viewed in Figure 1, they will be seen to form a continuation of the conveyorsection A which includes the rollers l9, and thus the product, packages, or the like, to be treated, may be given a steady movement from, one 'end of the apparatus to the other, such movement being continued within and throughout the treatment section B.

Onto-the rotary members 23 in section B (Figures 1 and 2) there is to impinge, as later pointed out, a discharge preferably in the form of a corona-like discharge and, turning now to Figure 3, the Wall or walls of the members 23 are to form the dielectrics or capacitances between the lower end of such discharge and a conductive means 24 within the tubular members 23. This conductive means may take any appropriate or suitable form andmost conveniently is in the nature of a metallic coating or metallic sheet lining related to the inside surface of the tubular members 23, the latter being preferably relatively accurately made to have substantially uniform wall thickness. The right-hand ends of the tubular members 23 have mounted therein metallic shafts 25 (Figure- 3), the latter being secured in place in any suitable manner, as by a cement 26, and being in electrical connection with the metallic coating 24, as indicated at 24* in Figure 3. By way of the shafts 25, the right-hand ends (as viewed in Figure 3) of the rotary members 23 are rotatably supported and maintained in alinement with-or in the same plane as the rollers 19 and 20 of sections A and C, the shafts 25 being rotatably supported in bearings 21 which conveniently and preferably are of the metallic oil-less type and acting therefore to continue the electrical circuits continued by the shafts 25 because of their connection to the linings 24 of their respective tubular members 23} Considering now the support of the oil-less bearings 21 and still referring to Figure 3, the

bearings 21 areeach secured to or supported by upright conductive means, preferably taking the form of sheet metal tubes 28, one for each rotary member 28 (see Figures 2 and 1) and all alined and mounted in spaced relation and preferably 5 parallel to the vertical front wall lt of the housing l0 (Figure 1);

As is better shown in Figure 3, each vertical tube electrode 28 is preferably cut away at one side thereof in order to receive therein the bear- 10 ing 21 which is secured in place in any suitable manner, as by screws, or the like, each bearing 21 being thus in good electrical contact or connection with its respective electrode tube 28. Preferably, also, the upper and lower ends of the ver- 15 ticai tube electrodes 28 are rounded over, as by plugs 28 and'28 (Figure 3) thereby avoiding sharp corners or points, the plugs thereby serving'also as convenient means, being recessed, to

receive respectively the studs 29 and 30 of 20 insulating plateor beam-like members 29 and 30, respectively, the latter being made of any suitable solid dielectric material, such as laminated bakelite.

Members 29 and '30 are preferably of identical g5 shape, the one (member 28) projecting upwardly from the bottom or base 10 of the housing to which it is secured, as at 31-32, and the other being inverted and projecting downwardl from an upper portion of the housing III to which it is secured asat 33-34, and hence at two widely spaced points. In Figure l the juxtaposed relation of the dielectric supports 28-30 is clearly shown, and it will be seen that each is shaped,

somewhat in the form of a horizontally elongated X, thereby providing a relatively long path from any one of the vertical electrode tubes 28 to any one of the points 3|, 32 or 33, 34 of connection of the members 29 and 30, respectively, to the grounded housing It. As will later be pointed 40 out, the electrode tubes 28 are maintained at a relatively high potential and by this construction ofthe solid dielectric supports any tendency of loss of energy by leakage along the supports to ground is dependably negatived. Also, the 45 rounded configuration of. the members 28 avoids undesired brush discharge or similar loss of energy,

Each member 28 (see Figures 2 and 3) being belt-receiving grooves thereof are properly proportiohed to the diameters of the respective roller members (in the illustrative embodiment all of these diameters are preferably equal), I cause thus insulated from the vertical wall lo 'or the w action, particularly where the diameters of them a single endless belt 42 to be effective upon and 55 in all oftthese belt grooves or belt pulleys and achieve that arrangement preferably in the fol lowing way:-

Extending underneath the roller sections A, B

and C, and closely positioned to the bottom "3 7 (Figure 1) of the housing I0, is a shaft 36' mounted in bearings 31 and 38 at the respective right and left-hand ends of the bottom or base 10. Bearings 31 and 38 are mounted for vertical adjustment on elevating screws 39 and 40, respec- 7 tively, and thereby the vertical spacing in a downward direction of the shaft 36 from the 'rollers of. the conveyor means may be determined at will, for a purpose later described. Moreover, the shaft 36, being metallic, is preferably mounted'close to the bottom ll) of the housing l0 and also considerably to the rear (as viewed in Figure 1) of the vertical condenser electrodes 28, and thus is well spaced from high potential parts.

Spaced along the shaft 36 is a series of sheaves 4|, one for each successive-two or pair of the roller members of the conveyor means A, B, C, the sheaves 4| being grooved, like the roller members, to receive a round belt and being positioned, as is better shown in Figure 1, so'that the planes of the belt grooves therein fall between such successive pairs of. roller members.

A single belt 42, preferably a round leather belt (or any other Suitable and preferably non-conductive material) coacts with the driving sheaves 4| and the rollers to drive all of the latter; it extends from the endmost idler 5| (at the righthand end of side. frame l3) upwardly into and over the belt grooves |9 of the endmost two rollers IQ of section A, thence downwardly to the endmost sheave M on shaft 36 about which it passes to continue upwardly over and into/the belt grooves I9 of the next two rollers l9, thence downwardly to the next sheave 6| on the shaft 36, and so on with respectto each successive pair of rollers in all three groups A, B and and related or allocated sheaves 6| on the shaft 36, the turn in the belt for eachsheave 6| and pair of roller members being as isbetter shown in Figure 3. The belt 42 finally comes over -the belt grooves 26 of the last pair of rollers 20" of the group C (see now Figure 1), whence it extends downwardly over the left-end driving sheave 4|, on shaft 36, from which it extends upwardly (see left-hand portion of Figure 1) about an idler 50 mounted on the insulating side frame I 3, and from idler 50 it extends horizontally throughout and underneath the entire extent of -the rollers 20, 23 and illv to idler 5| at the extreme right-hand end of theinsulating side frame l3, whence it goes upwardly to the first pair of rollers l9, as already above described, the belt being endless.

The shaft 36 is driven by an" electric motor 52 or other suitable source of driving energy '(Figures 1 and 2) preferably positioned at the 'side of the endrnost rollers of the section C and secured to the bottom ll] of the housing l0. Any suitable driving connection, such as a chain and sprocket drive- 46, extends between the motor and the drive shaft 36.

The rollers of conveying-means A, B, C are driven to give the products a suitable rate of movement, preferably a rate that matches or suits the rate of discharge of the products, where the latter are packaged, from a packaging machine stationed at the rightof the apparatus.

The motor 52, upon being energized, therefore effects a movement of the belt 42 throughout the circuitous path above described, and the belt being in engagement with the belt groove of each roller or rotary memberof the conveyor means A, B, C drives them at uniform surface speed, all

in counter-clockwise direction, as viewed in Figmembers 23 in the treatment zone or section B and the shaft and its pulleys sufiiciently long belt lengths to minimize or negative loss of energy by possible leakage currents along the belt tension of the belt to compensate for belt stretch that might accompany long-continued operation may be achieved by adjusting the shaft bearings 31 and 38 in downward direction by the adjusting screws 39 and 60, respectively, and it will be noted that, though the belt 32 is of substantial length and the aggregate stretch or increase in length may be substantial, only a small adjustment of bearings 31 and 38, becaute of the numerous loops of the belt that extend downwardly to the numerous pulleys on the shaft, need be made to take up what otherwise might appear to be a substantial belt elongation.

Reverting now to the treatment zone and certain parts coacting with the above described dielectric or glass tubes 23 of section B, it is first of all to be noted, referring now to Figure 2, that the products to be treated, illustratively packaged products, move in a straight line from the righthand end of the conveyor means A, B, C right on through to the left-hand end, the path of movement being substantially alongga straight line and hence only those portions of the electrically coacting tubular members 23 of the intermediate section B that are in line with the rollers l9 and 20 of sections A and C are effective in the prodnot-conveying action and it is, therefore, with respect to such portions of the rotary tubular members 23, that the above-mentioned electric discharge is to be concentrated or made effective; accordingly, I mount above these portions of the members 23 a high voltage electrode arrangement which, in so far as certain other features of my invention are concerned, preferably takes the form or forms hereinafter described in detail, it being noted that whatever fom'i or forms the high voltage electrode structure assumes, the extension or elongation of the members 23 forwardly of the apparatus insures also the positioning of the vertical condenser electrodes 28 sufliciently remote as to provide adequate space for themounting and supporting of the high voltage electrode arrangement.

In the-space thus provided, and preferably directly over the above-mentioned effective covering portions of the members 23, I position a suitableinsulating structure generally indicated at 66 (Figure 1)- and it may and preferably does include a lower ring member 6| from which a suitable number of struts extend upwardly, preferably diagonally or inclined as it were to join an upper ring member. 62 supported by the frame or housing In in any suitable manner for adjustment in an up and down direction, as is indicated by the metallic bracket 63 (Figure 1) connected to the upper insulating ringportion 62 in connection with a manually operable elevating screw 64, the construction of the insulating structure 60 and, its mounting conveniently and preferably taking the form of that described in detail in 6 portions to the grounded shaft 36. Appropriate 5 my above-mentioned application. i 5

The lower ,ring member 6| of the insulating support 60 thus "insulatinglysuports a suitable number, illustratively eight rotating electrodes,

H, 12, 13, HI, I5, 16, I! and 18, each electrode the plane of the conveyor means A, B, C, and hence parallel to the path of travel of the packages or products D carried thereby, are coincident but extend along a line E-E (Figure 2) that is at an angle or diagonal to the otherwise straight line of travel of the product or packages D. I

The electrodes II, 12, etc. (Figures 1 and 2) are preferably of identical shape and dimension and hence the lowermost points therein fall in a straight line, the spacing of which from the conveyor means, or more specifically from the coacting capacity-forming tubular members 23, may be varied or predetermined by raising or lowering the insulating structure 60 as by the elevating screws 64. All of these electrodes are maintained at a high potential, a potential on the order of 150,000 volts and preferably an alternating potential of relatively high frequency, such as a frequency on the order of 640 cycles per second. Each succeeding electrode of the group rotates about its horizontal axis in a direction opposite from the direction of rotation of the next preceding electrode. Accordingly,

electrodes H, 13, 15 and Ti rotate all in one direction and electrodes 12, l4, l6 and 18 all rotate in the opposite direction, as indicated by the arrows in Figure 1.

.A suitable high potential, illustrative]; as above-mentioned, may be applied to these electrodes in any suitable manner; preferably I employ a means and arrangement like that described in my above-mentioned application, to which reference may be had for certain details. That preferred arrangement includes a transformer casing I0 carried by the upper part of the housing I0 (Figure 1) and containing a high frequency transformer Bil-8|, whose low v0ltage winding may be supplied with suitable high frequency energy, preferably at low voltage, from any suitable source such as an alternator 82, and whose high voltage winding 8| (the ratio of transformation being suitable to cause the winding 8| to produce a voltage on the order 'of 150,000 volts) having its one terminal grounded as at 83, and hence grounded to the housing I0, and hence connected to the front wall H) which, it will be recalled, forms with the vertical condenser electrodes 28 an air condenser earlier above mentioned; the other terminal of the high voltage winding 8| is carried by conductor 84 out of the casing 10 through. a high voltage terminal construction 85 depending from the casing 10 and positioned substantially coaxially with and within the ring-like or cylindrical insulating structure 30 above described, whence the highpotential of the winding 8| is communicated to the electrodes 1 I, '12, 13, etc., the insulating structure 6|] thus dependably insulating these high voltage electrodes from the grounded housing and other parts of the apparatus.

With the high voltage circuit thus completed, bearing in mind the conductive coupling or relation of the interior lining or coatng 24 in the glass tubes 23 (Figure 3) with their respective condenser elements or tubes 23, as earlier above described, there takes place a localized rupture of the air spaces or regions immediately underneath each rotating electrode toroid II, 12, 13, etc., and extending downwardly to and terminating in the outer surfaces of the two rotary dielectric members 23 immediately underneath each rotating electrode. Thus, referring to Figure 2, where, as earlier noted, I -provide sixteen glass tube members 23, it will be noted that I have provided eight diagonally arranged rotating electrodes ll, 12 18, one for each pair of tube members 23 and that, moreover, the lowest point in each rotating electrode falls in a vertical plane that passes through the pair of rotary tubes 23 immediately underneath it and to which it is thus virl'izually allocated for immediate coaction electrica y.

This local rupture, because of certain other" features of arrangement and action, is preferably in the form of a finely divided corona discharge,

being thus made up of a multitude of individually minute or fine corona streamers for purposes later, described, disruptive discharge or sparkover being prevented by reason of the action of U other capacitances in the circuit of each rotating electrode. More particularly, it will be seen that, where each rotating electrode coacts with illustratively two tubular members 23 immediately underneath it, the metallic linings or coatings 24 of the latter extend the high voltage circuit, forming capacitances with the corona discharge that impinges upon the outer surfaces of the two tubes 23 (the dielectric of the latter forming the intervening dielectric), whence the high voltage circuit of that particular rotating electrode is extended by the air condenser formed by the two vertical tubular condenser elements 28 to which the coatings 24 of the two rotating members 23 are conductively connected. Those particular two condenser electrodes 28 form with the front wall In of the housing (the housing completing the return circuit to the other or grounded terminal of the high voltage winding 8| of Figure 1) an air condenser which is of itself sufilcient to withstand the maximum voltage of the transformer winding 8| without rupture or breakdown.

From each electrode member TI, 12, etc.,therefore, the high voltage circuit is extended virtually in two parallel paths where each electrode coacts with two rotary members 23 and their respectively related condenser elements 28.

From this relationship of parts, certain unique advantages follow. For example, the metallic coating or lining (or electrode) 24 within each tube 23 is relatively narrow but elongated in dimensions when considered in the plan view of Figure 2, for example, and the flux emanating from the lower curved or spherical area 01 each rotating toroid shaped electrode 1|, 12, etc., is drawn toward and thus concentrated by the conductive coating 24, the encompassing and rotating glass or other dielectric of the rotating tube member 23, being uniform, insuring uniformity of concentrating action and permitting some but not a detrimental ,amount of spreading of the emanating flux and hence of the corona-like mass of streamers. Where the radii of curvature of the rotating electrodes 1|, I2, etc. are relatively large, as in the illustrative embodiment above described, and in order to cause a greater area around or at the under or lowermost side or portion of each electrode to be effective as a coronadischarge-emanating means, particularly in the direction of the axis of rotation of the rotating electrodes, I preferably cause, as already noted, each electrode to coact with more than one and illustratively two rotating tubular members 23, and hence with more than one and illustratively two conductive coatings or members 24. Accordingly, the extension of the member or members 24 in the direction transverse to the axis of its associated rotating electrode causes an increase in the length of the corona-emanating area of the electrode in the direction of the circumference thereof while relating a conductive member 2d, insulated by the dielectric of the member 23, to each side, as it were, of the substantially median or central vertical plane (as viewed in Figures 1 and 2) through the electrode, achieves an increase in the other dimension (in the direction of the axis of rotation of, the electrode) of the corona-emanating area thereof.

Thus, with relatively large radii of curvature of each electrode member H, 12, etc., I am enabled to cause, due to such coactions as have just been mentioned, the production and maintenance of a mass of corona discharge or streamers which, in horizontal cross-section, is of relatively large area or dimension.

It is accordingly eight such massesof corona discharge that the arrangement of the eight rotating electrodes H, 12, etc. with their coacting Parts achieves and in order to give the apparatus a capacity for handling products or packages whose width or dimension in the direction of the axis of the conveyor rollers 19 and 20 is relatively large compared to the axial lengths of these rollers themselves, these electrodes are arranged along the diagonal E-E of Figure 2, as above described, so that any package or product, moving along the conveyor means A, B, C from the right to the left (Figures 1 and 2) no matter what its width within the range of the lengths of the conveyor rollers, is caused to have each portion or segment in the direction of its length or path of travel subjected to the ionizing action and 'corona-like discharge before it emerges from the treatment zone or section B.

For example, while the discharge action of electrode 18, may, because of the dimensions or the package or article, he of insufficient dimension transversely of the path of travel to effect complete sterilization, such portions thereof as are not sterilized by electrode 18 are nevertheless effectively treated and sterilized by the action of one or more or all of the succeeding electrodes, as the package or product continues to'move toward the left.

In this connection, the individual condensers above described in the circuit of each rotating electrode H, l2, etc. achieve certain other advantageous actions. For example, and considered broadly, itv will be seen that the energy output of the high voltage source 8| of energy is subdivided into a multitude of parallel circuits, illustratively and ultimately sixteen in number, one for each member 23 and its related condenser electrode 28. Should an article or a portion thereof or a portion or the whole of the contents of a package of material be, for some reason, in such a cpndition as, for example, wet, so as to give thepackage or'material an unusual or unexpected permittivity, making that portion or part of the product of unusually high conductivity, the individual parallel circuits and the in dividual capacities therein included, for example, the condenser between the electrode discharge and the metallic coating 24 (with the dielectric of member 23 as its dielectric) and the capacity formed by an individual condenser tube electrode 28 and the front wall i of the housing, are selfprotective and, moreover, the latter-mentioned condenser acts at once to limit the currentflow in its particular circuit to a safe or maximum permissible limit, thereby preventing the dissipation in that particular circuit of all of the high voltage energy and preventing therefore the shunting away-from the remaining parallel circuits in which sterilization is being carried on, of

These various parallel circuits, therefore, are

mutually interacting and mutually self-protecting and insure continuity of sterilizing action in spite of what might otherwise be circumstances fatal to sterilization of products or materials already in the treatment zone.

Accompanyingv the above described action is the coaction of the oppositely rotating electrodes upon packaged products, and by this coaction there is overcome and dependably negativedany tendency or action that deflects or refracts the discharge away from the vertical end or side walls of the package itself, as the package moves into or through'the mass of corona discharge that is individual to each electrode and which streams downwardly from the above described relatively large surface area of the lower portion, as viewed in Figure 1, of each rotating toroidelectrode, and in this connection reference is now made to Figures 7 and 8. In Figure 7 a package D is shown, as viewed from the right-hand end 01 Figure 2, in relation to an electrode, for example, electrode 11, that rotates in clockwise direction when viewed from that end of the apparatus, and in Figure 8 is shown the same package D in relation to the next succeeding electrode, for example 16, whose direction of rotation is reversed.

In Figure 7, also, there is indicated, as by the stippling TI, so much of the effective dischargeemanating area of electrode ll as would be visible or apparent when the electrode is viewed as seen in Figure 7, and with the electrode moving in clockwise direction, it has a tendency to sweep,

as it were, the individual discharge or corona tendency of the flux or discharge to follow the vertical side wall, or other factors.

But whenv the package D comes into the discharge zone under the next electrode 16 (Figure 8) oppositely rotating, the rotation of the latter tends to sweep the flux, emanating from the area 16 thereof, in a direction toward the right, and hence toward and beyond the right-hand vertical wall of package D. With the discharge streamers moving in that direction, however, the portion of the contents to the left of the right-hand wall of package D (Figure 8), and which might have escaped sterilization under electrode 11 of Figure 7, is now thoroughly sterilized. Due to the inclination of the axis E, E (Figure 2) of rotation of the toroidal electrodes, this sweeping aEfon or movement of the streamers of the discharge is in a direction also at an angle to the vertical front and end walls of the package, and due to the opposite directions of movement of sweeping of the discharge relative thereto, as will now be clear from what has been above said in connection with Figures '7 and 8, the portions of the product within the package and immediately adjacent the front and rear vertical end walls of the package cannot, in a similar way,

escape sterilization, and thus uniform sterilization electrodes 1|, I2, 13, etc., for example the eight illustratively above described, there is achieved a repeated reversal of sweeping movement of the discharge or corona streamers with respect to the vertical walls of the package, and thus certainty of complete sterilization is assured.

The regions of flux concentration or the masses of corona streamers respectively individual to the various electrodes are, furthermore, as is now clear, of sufficient dimension in a direction transversely of the conveyor means A, B, C (Figure 2) that, when viewed along the length of the conveyor means, they overlap and form a barrier as it were, of dielectric stress or of corona discharge that extends entirely across the conveyor means,

' due to the diagonal relation of the axis E, E of Figure 2, and thus the passage of any product or article within the dimensions of the conveyor means and along the latter is effective to cause every portionthereof to move through this barrier and thus to be sterilized.

The action of destruction of the insect life follows with great certainty; the product, illustratively flour, corn-meal, cereals, or the like, has a higher average permittivity than the air intervening the particles of the material itself and of the air which the material itself displaces in the treatment zone or regions, causing a redistribution of voltages in the high voltage circuit. As a result, dependable ionization throughout the material and particularly within the packages where it is packaged, takes place as does also corona discharge, the latter occurring at a lower point on the voltage wave with a consequent increase in its duration. contaminating life has substantially infinite permittivity, being in effect electrically conducting, the insects, larvae, pupae, eggs, etc.,.thereof, are sought out by the corona streamers, the latter pass therethrough, and bring about their destruction.

Puncturing of the pasteboard or other nonconductive material of the package, where the material is packaged, is dependably guarded against. The material of the packages or cartons acts as a condenser dielectric or dielectrics which becomes serially related to the dielectrics of other capacitances in the high voltage circuit or circuits, such as the glass wall of the member or members 23 (Figure 3), or the air dielectric of the condenser 28l0 (Figures 2 and 3), andthe latter capacities are proportioned so that the resultant redistribution of voltages throughout these serially related condenser dielectrics is such that the'voltagegradient across the material of the carton is below the puncturing gradient and hence puncturing of the walls of the carton is positively precluded. Also the preferred mode of operation wherein spark-over or disruptive discharge in the treatment zone or regions, as distinguished from the streamer or corona-like discharge above described, is prevented, coacts to guard against damaging the material of the carton or package.

The large-surfaced toroidal form of electrodes II, I2, 13, etc. achieves other: advantages besides the emanation of corona discharge; stated difierently, heating or other physical change is minimized because I am enabled to avoid steady or constant emanation of discharge from a point or points and instead spread the discharge as it Because the emanates over a relatively large area (see portions 'l! or 1B? of Figures 7 and 8, for example), the surface or surfaces of-which, however, are constantly being replaced or renewed due to the rotation of the toroidal electrode. The speed of rotation is preferably relatively high, say on the order of 4000 R. P. M., thus making any portion of the area or surface of the electrode that is presented toward the parts 23 for corona emanation effective only for an infinitesimally small interval of time.

By raising or lowering the insulating structure 60, I mayvary the character of discharge action in the treatment regions or zones and I may also accommodate the apparatus to different vertical dimensions of products or packages, or the like. The toroidal electrodes, per se, are replaceable as hereinafter described, and I may in that manner vary their effective diameter as well as other radii of curvature, and thus vary accordingly the character, nature and other characteristics of the action in the treatment zone to suit practical conditions as may arise.

Considering now in detail the construction, mounting and driving of the toroidal electrodes, it is first to be noted as appears from Figure 1, that the toroidal electrodes are pairedto form as it were as many units structurally as there are successive pairs of electrodes; thus electrodes II-12 are paired to form a single unit, the next two electrodes 13-14 are paired to form another unit, and so on, thus simplifying the mounting and supporting of all of the electrodes from the solid dielectric supporting structure 6|]. Since these pairs or units of electrodes and their drives and mountings are substantially identical, it will suflice to describe in detail one pair or unit, illustratively that unit which includes the electrodes H12 of Figure l, and accordingly reference may now be made to Figures 5 and 6 of the drawings in which the structure of that unit is shown on an enlarged scale and in detail.

As is better shown in Figure 5, the double electrode unit comprises two structures BI and 92 which in turn are substantially identical, including respectively supporting arms 93 and 94 which, when placed back to back, as shown in Figure 5, and secured together, form the double electrode and driving structure or unit. Accordingly, it will suffice to describe in detail one of the structures 9l92 and hence consideration may now be given to the structure 9| which is shown in cross-section in Figure 5 and in side elevation in Figure 6, as seen along the line 6-6 of Figure 5.

The arm 93 (Figures 5 and 6) is concaved or hollow as at 95, and its lower end is disk-like in shape (see Figure .6) as at 93 being bored out as at 93 (Figure 5) to receive therein a sleeve member 96, hereinafter called the stator sleeve. Stator sleeve 96 has built onto it or supports the stationary element of an electric motor, preferably an alternating current motor of the induction type, and hence that stationary member is illustratively termed the stator. The stator comprises a stator core 91 built up of laminations which are centrally apertured to fit onto stator sleeve 96, abutting at the left against a shoulder formed by a stepped and larger-diametered extension 96 of the stator sleeve 96 between which and a threaded collar or nut 98, threaded onto a threaded intermediate portion of the stator sleeve 96, the stator core 91 is securely clamped. The nut or collar 98 is rigidly secured to the portion 93 of the arm 93 by screws 99 (Figures 5 and 6) which thus hold the stator sleeve 96 well seated in, the bore 93' (Figure 5). The stator core 91 may also be 'provided with annular guards l-l0l of suitable sheet material, L-shaped or flanged in cross-section, and one on each side of the core 91, secured in place by rivets I02 which thus also aid in clamping the laminations of the core 91 together; The latter, moreover, is peripherally slotted to receive suitable coils to form a winding I03, one termihal of which is grounded to the core 01 asat I00, and the other terminal of which is carried by conductor E05 through a suitable aperture in the sheet metal guard l0! and through a suitable channel or hole 93 in the disk portion 03, thus communicating with the hollow or concave portion 95 of the arm 93, whence the conductor is extended further as later hereinafter described.

The winding I03 may be of a character disclosed in my co-pending application filed of even date herewith, Serial No. 747,436, and the core 91 may also be provided with peripherally posltioned shading coils, as disclosed in the said ap plication but-not shown in the drawings herein. The induction motor of which this stator core structure forms a part is thus given self-starting characteristics. Z

The motor core that coacts with the stator core 917 is indicated at I06 and it is made up Of gg conductors, in the form of rivets, shown at I09.

This annular rotor core J06 is supportedfor rotation concentrically with the above-described stationary stator SL403 by a rotor housing generally indicated at H0 and comprising a disk-like a vertical end wall H0 and a cylindrical or drumlike wall H0 which carries an inwardly directed flange 0 against which the rotor core I06 is seated, the cylindrical portion illl being bored out snugly'to receive the annular rotor core Hi6.

$3 A complementary member ill has a vertically extending annular end wall ill with a cylindrical portion lll shaped at its left-hand periphery to telescope into the cylindrical portion llil of the rotor support H0, and the complementary 50 member I l i is secured to the rotor support 0 by screws 2 which, when driven home, cause the portion Ill tosecurely clamp the rotor core I06 between it and the radially extending flange H0".v r W 55 The rotor housing or support 0 has its disklike end wall H0 interiorly counterbored as at llfl to snugly receive therein the disk-like head or end flange b of a shaft H3 which extends into and coaxially with the stationary stator 80 sleeve 96, member 0 being secured to the end flange I it as by a suitable number of screws H4.

Shaft M3 isin turn rotatably supported by and within the stator sleeve 98, whereby rotor core I06, now encased by the parts ill and H0,

65 may freely rotate with these parts, aboutv the axis of the rotor sleeve 95, the right-hand end of annular member til being apertured and recessed about the periphery of its axis to receive felt or similar washers iifl which bear against, and thus form a dust-proof seal with, the cylindrical face of the hub-like extension (toward the left, as viewed in Figure 5) within which the counterbore 03 is formed. Thus all the working w parts of the motor are totally enclosed and sealed, including also the parts presently to be described.

The shaft 3 is rotatably supported in the stator sleeve 96, preferably by suitable anti-friction bearings, illustratively ball bearings and H6. The outer race H5 of the bearing H5 is received within and held by the stepped or larger-diametered portion 96 of the sleeve 96, a spacer ring or washer M0 being interposed between it and the head N3 of the shaft H3, while 10 the inner race H5 rests at its left-hand end against a shoulder of the stepped shaft H3; its right-hand end is abutted by a sleeve H'l which extends toward the right, being stepped or reduced in' diameter, as is also the extreme right- 15 hand end portion llil of the shaft H3. Upon the latter is received the inner race Hi5 of the anti-friction bearing H0 and it abuts against theright-hand end portion of the sleeve I IT. The reduced end portion H3 of the shaft H3 is 20 threaded to receive a nut H8 which bears against the inner race lit and clamps the latter and the sleeve Ill and the inner race H5 against the left-hand shoulder of the shaft H3, thereby rigidly fixing these parts to rotate with the shaft 25 H3. The outer race H6 of the bearing H6 is seated, fitted or secured within the right-hand end of the stator sleeve 96 preferably abutting against a shoulder formed in the latter, as shown in Figure 5. 80

Accordingly, the stator I06 with its housing parts ll0-lll is thus supported for free rotation relative to the stator 91 and its stationary supporting sleeve 96, and to rotate also relative to the latter, the entire assemblageof these parts being, as will now be clear, capable of assembly relative to the supporting arm 93 and detachably so, by screws 99 and the related interfitting parts.

The complementary housing member. III is 40 provided with a radially extending peripheral flange lil preferably integrally formed therewith, while the housing or rotor support 0 is counterbored as at 0 to form a seat for a ring-member I20 which is provided with a peripherally or radially extending flange I20 forming a juxtaposed part to the above-mentioned radial flange HIP, but being detachable by rea son of the detachable securing of the ring-member I20 to the member H0 by the screws I2l.

When ring-member I20 is detached, the toroidal electrode Il may be slipped, in an axial direction, onto or over the housing portions 0 and II l to bring its right-hand portion in abutting relation to the flange ll I, whereupon the ring-member I20 is replaced, bringing the juxtaposed flange l20 into engagement with the lefthand part of the toroidal electrode 1|,the outside diameters of the parts to the inside of these flanges being such as to closely match the inside 50 diameters of these side portions of the electrode H, the latter being thus securely but detachably mounted onto the rotating rotor housing ll 0l II and coaxially therewith. I

The toroidal electrode II is preferably made 5 hollow and hence preferably made of sheet-like metal, preferably nickel or a nickel alloy, and may be formed in any suitable way as by spinning, casting and machining, by electro-deposition, or the like. Referring to Figures 5, 1 and 2, the ex- 0 temal surface of the electrode 1i, generally toroidal in shape, is of large radius of curvature as seen in cross-section, as in Figure 5), the large radii of curvature being accentuated by distribution peripherally about a large diameter through the axis of rotation of the electrode itself.

Where made in hollow form or shape, the electrode TI may be made to coact, due to its resultant inherent springiness, in a yielding gripping thereof between the securing parts III and I2Il.

As illustrative of the radii of curvature or dimensions of the electrodes II, I2, etc., and referring to the electrode II of Figure 5, it may be noted that the maximum diameter of the electrode H may be on the order of 11" and the radius of curvature in cross-section or in a plane through the axis of rotation, may be on the order of 2".

The upper ends of arms 93 and 94 (Figures 5 and 6) have respectively integrally formed therewith cross-arms I22 and I22 parts I22 and 93, and parts I22 and 94 being virtuallyi-shaped. The ends of cross-members I22 and I22 are provided with split bushings I23 and. I24, respectively, the axes of which, however, extend parallel to the axis of rotation of the electrodes II and I2, respectively, the split bushings being given a clamping action by reason of the clamping screws I25 related thereto. The arms I22 and I22 and the bushings I23 and I24 are interio'rly channeled or hollowed out as at I26 forming channels through which the conductor I95 may be led.

The arm 94 of the structure 92 (Figure 5) is thus the same as the arm 93, being an exact duplicate thereof and having therein a conductor I21 (Figure 5) leading to the motor which drives the electrode 12. with its electrode I2 and the encased driving inotor therefor, is laid against or face to face with the L-shaped arm 93--I22 and the two are secured together as by screws I28 at the upper end thereof and as by a bolt I29 (Figure 5) fitted into registering slots I30 (Figure 6) in the lower ends of the two arms, thereby providing the double electrode unit structure II'I2, by way of illustration. The latter will thus be seen to have a T-shaped support, the cross-member or arm I22 of which is formed by the oppositely extending parts I22 and 122".

In thus assembling the parts of a, single double electrode unit, and with the motors thereof uniformly constructed as to direction of rotation, the backing of one motor against the other, as it were, causes one electrode or motor to rotate in one direction and the othef'motor and electrode to rotate in opposite direction about the now alined coincident axes or comrnonaxis thereof.

Thus, the four pairs of oppositely rotating electrodes earlier above-mentioned are each provided with a cross-member I22 with the split bushings I23-I24; the latter are assembled to two metallie and preferably tubular supports I3I--I32 (Figures 6 and 1), the tubular support I3I (Figure 6) being apertured at intervals corresponding to the spacings of the cross-members I22 or bushings I23 therealong, so that the conductors I95 and I21 of the motors of each pair may be brought into the tubular support I3I, for a purpose later described.

The tubular supports I3I-I32 are parallel to each other and lie in a plane parallel to the plane of the conveyor means. in section B (Figures 1 .and 2) and are held fixedly in the lower ring- L-shaped arm 94I 22 cured to the ring-portion BI by clamping members I33 and I34 (Figure 1) which extend peripherally of the ring-member BI to an appropriate extent and overlap the upper edge thereof, thereby to avoid undue concentration of the weight of the illustratively four pairs of electrode and driving structures.

The split bushings I23-I24 securely clamp the various cross-members I22 to the spaced tubular supports I3I and, I32, the arrangement, moreover, being such that the spacing of the paired electrodes or units along the tubular supports may be varied when desired; and the same clamping action also insures a good electrical contact between the tubular supports and the T-shaped arm or frames 93-94-I22 (Figures 5 and 6) of the double electrode structure so that, when the high voltage side of the transformer winding 8i (Figure 1) is extended by conductor 84 through the insulating bushing or terminal construction 95 and by a conductor I35 to one or both of the tubular supports I 3I-I32; the latter as well as the electrode units or structures supported thereby are placed and maintained at the high potential of this transformer, the electrodes II, I2, 13 coasting with the other parts as already above described in detail.

Referring back to Figure 5, in order to avoid any detrimental action upon the anti-friction bearings by the passage of any current therethrough from the stationary motor parts to the rotating motor parts, I provide a recess H3 in the left-hand face of the shaft head 3 the recess being outwardly or radially exposed to the inner face of the left-hand end of the stator sleeve 96. In this recess I mount a brush I4I extending radially and contacting with the inner cylindrical face of the portion 96 of the stationary stator sleeve 96. 'The brush I may be of any suitable construction; for example, it may be in the form of a carbon, copper, sponge copper, or the like, suitably spring-pressed into contact with'the inner face of the stationary sleeve 96. As the electrode II with its rotor housing and hence with the shaft II3 rotates, the brush I4I sweeps about the inner face of the portion 96 'of the stationary stator sleeve 96, and makes and the anti-friction bearings and thus avoids any possible detrimental actionon the latter. v

The recess 3* in the shaft head H3 and hence the brush therein containedis accessible for adjustmentfreplacement or repair, from the exterior, by way of a threaded aperture in the vertical wall portion I II! of the rotor housing, the aperture being closed by athreaded plug I42.

Suitable means for lubricating the bearings I I5 and IIS are also provided and they may take the form (see Figure 6) of a lubricating duct I43 extending radially through the portion 93 of the arm 93 and communicating with the innermost (right-hand, as seen in Figure 5) end portion of the counterbore 93', therein; through this lubrieating duct I43 suitable lubricant may be forced or injected into this endportion of the counterhore 93 and hence to the bearing H6, and through the latter and by way of the spacing between the sleeves 96 and I" (Figure 5) to the hearing II5. The duct I43 (Figure 6) is closed by a, threaded plug I44.

As above pointed out, one terminal of the motor windings I03 is grounded (see the ground at I03 in Figure 5) and this, being true as to all of the motors of the electrodes H, I2, I3, etc. (Figures 1 and 2) the same side or terminal of all of these windings is to be electrically connected, through the motor parts 'and arms 9394 and cross-arms I22 to the metallic tubular supports I3I and I32 to which (see now Figure 1) the high voltage side of the transformer winding 8i is connected as above described, that one side or terminal of all of these windings being thereby electrically extended into the transformer casing Ill by way of conductor I35, high voltage terminal 85 and conductor 8% (Figure l); conductor 84 is also connected to one terminal of the secondary winding N5 of a low voltage, low frequency transformer whose primary winding IE5 is connected,

as diagrammatically indicated in Figure l, to a suitable external source WI of alternating current energy, such as the usual A. C. power supplycircuits of 110 or 220 volts, 60-cycle current.

The secondary winding I 45 is, because of its connection to the high tension conductor 84, at the high potential of the latter, but the transformer IMF-I65 is insulated for that high potential, as described in my above-mentioned copending application, and thus the primary winding M6 and its circuit to the source It! is adequatelyprotected from this high potential.

The other terminal of the secondary winding M5 is connected by conductor m8 to a separate conductive member M9 in the insulating bushing 85 (the detailed construction of which is shown in my above-mentioned application) and is insulated from the high voltage conductor therein for a voltage on the order of 110 or 220 volts. Conductor M9 is connected to all of the conductors I05 and I21 (Figures 5"and 6) which are snaked through one of the tubular supports, for example support I3I, and which lead to the other terminals of the windings I03 of the various motors. And thereby the circuits to the stator windings of these various motors are completed so as to supply energy thereto and efiect rotation of the toroidal electrodes II, I2, I3, etc., in the manner and with the actions and results certain of which were 11- lustratively described above in detail. Considering further certain of these actions, reference might again be made to the high speed of movement ,or the high rate of peripheral velocity of the active surfaces of the toroidal electrodes; this velocity is, as above indicated, on the order of 10,000 per'minute. Because of this high velocity, the desired character of discharge is effectively maintained. For example, the active electrode surfaces are effectively cooled and such heat rise as would materially facilitate the disintegration of the electrode metal orthe separationfrom the electrodes of metallic particles is minimized and thereby tendencies toward thearc type of discharge negatived.

Furthermore, the high velocity of electrode surface movement achieves also a movement, at relatively high velocity, of the air in the discharge gap or in the treatment zone, and thereby the ionized air in the treatment zone is rapidly removed. There thus results substantially constant or uniform voltage of disruption.

"The large cross-sectional area of the coronalike discharge emanating from each toroidal electrode results to a substantial degree from the high peripheral velocity of the electrode surface.

As earlier above noted, two roller members of the conveyor section B are allocated to each toroidal electrode, in the preferred embodiment of my invention, but that illustrative arrangement is not to be interpreted in a limiting or restricting sense, for under some circumstances I may allocate to each toroidal electrode only one such roller member or more than two. To better understand certain aspects of the coaction of these parts it might first be noted that, whatever the allocation of a lower roller member or members to a toroidal electrode, I prefer to achieve, as nearly as is practicable, substantial equality between the maximum voltage gradient and the average voltage gradient across the treatment zone between the parts. Such substantial equality is electrically best or most simply achieved if there were juxtaposed or allocated to a toroidal the radius of curvature of a toroidal electrode, as

viewed in Figure 5,'is on the order of 2", the radius of curvature of a single roller member allocated to it should be about the same, and with .such a relation of the parts the maximum and average voltage gradients across the treatment zone or discharge region therebetween likewise approximate equality, where the maximum thickness of product or packaged product to be treated is on the order of say 6". A preferred ratio of minimum radius of curvature to maximum thickness of material to be treated is 1 to 3.

However, where packaged products are to be treated, it is desirable that the package or carton be at all times supported by at least two rollers. In practice, packages or cartons are met with whose dimensions are too small to be supported simultaneously by two rollers of a radius of curvature on the order of 2", and it is therefore impracticable to use rollers of such dimensions.

Accordingly, two or more roller members are allocated to each toroidal electrode and they are made of sufiiciently small radius of curvature to meet the mechanical requirement of the package or carton being supported simultaneously by at least two roller members, but they are at the same time proportioned with respect to the radius of curvature of the." toroidal electrode to achieve across the discharge region of the latter substantial equality of maximum and average voltage gradients.

Illustratively, therefore, where the radius of curvature of the toroidal electrode is 2" and where the minimum length of package in the direction of its travel along the conveyor means A, B, C, is 6", the two roller members allocated to each toroidal electrode, to meet the above mechanical and electrical conditions, have a radius of curvature on the order of 1 and are spaced center to center on the order of 2%". This specific embodiment is therefore to be interpreted as illustrative.

The rotation of the rollers in the section B of the apparatus, these rollers being made of solid dielectrical material, illustratively pyrex glass, or the like, and upon which the discharge impinges, is also highly advantageous in that the life of the roller members or the dielectric thereof is greatly increased. For example, any portion of the discharge-receiving surface thereof is not continuously in discharge-receiving position but is periodically removed therefrom, and, moreover, during such removal, is subjected to a desirable cooling effect or action. Deterioration or other detriment effects thereon is thus negatived.

It will thus be seen that there has been provided in this invention an apparatus in which.

the various objects above noted, together with many thoroughly practical advantages are successfully achieved. It will also be seen that the apparatus is o'fa thoroughly practical character, is of dependable operation, and well adapted to meet various practical conditions of use.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbei'ore set forth or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In electrical treating apparatus, in combination, means for moving a product to be treated along a given path, electrode means spaced from said path and comprising a plurality of rotatable toroidal electrode members, means supporting said electrode members offset one from another transversely of said path, means for effecting rotation of certain of said members in one direction and others in reversed direction, and means including a source of suitable potential connected to said electrode means for effecting discharge through the product moving along said path.

2. In electrical treating apparatus, in combination, means comprising a plurality of rollers of dielectric material for movably supporting a product to be treated along a given path, and an electric discharge circuit comprising electrode means above said rollers, a source of suitable potential, and conductive means within certain of said rollers and extending along the axis thereof for effecting discharge of products moving in said path.

4. In electrical treating apparatus, in combination, means comprising a plurality of rollers of dielectric material for movably supporting a product to be treated along a given path, and an electric discharge circuit comprising electrode means above said rollers, a source of suitable potential, said rollers being in the form of tubelike members, and conductive means within certain of said rollers for coaction with said source and said electrode means.

5. In electrical treating apparatus, in combination, means comprising a plurality of rollers of dielectric material for movably supporting a product to be treated along a given path, and an electric discharge circuit comprising electrode means above said rollers, a source of suitable potential, said rollers being hollow and made of a material like glass and having conductive means on the inside surface thereof and included in said circuit.

6. In electrical treating apparatus, in combination, an electric discharge circuit comprising a source of suitable potential, electrode means, rollers of dielectric material spaced from the latter for movably supporting a product to be treated in the discharge region of said electrode means, conductive means below the dielectric material of said rollers and coacting therewith to form an electrode for concentrating the discharge at the lower end of said discharge region, and capacity-forming means, one terminal of which isconnected to said conductive means.

'7. In electrical treating apparatus, in combination, an electric discharge circuit comprising a source of suitable potential, electrode means, rollers of dielectric material spaced from the latter for movably supporting a product to be e 7 treated in the discharge region of said electrode means, conductive means below the dielectric material of said rollers and coacting therewith to form an electrode for concentrating the discharge at the lower end of said discharge region, said conductive means comprising a plurality of means each individual to a roller, and a plurality of condensers, each having a terminal thereof connected to one of said individual conductive means.

8. In electrical treating apparatus, in combination, an electric discharge circuit comprising a source of suitable potential, electrode means, rollers of dielectric material spaced from the latter for movably supporting a product to be treated in the discharge region of said electrode means, conductive' means below the dielectric material of said rollers and coacting therewith to form an electrode for concentrating the discharge at the lower end of said discharge region, said conductive means comprising a plurality of conductive means each individual to a roller, a condenser electrode for each of said individual conductive means and electrically connected thereto, and a plate-like condenser electrode common to all of said individual condenser electrodes, for completing said circuit.

9. In electrical treating apparatus, in combination, an electric discharge circuit comprising a source of suitable potential, electrode means, rollers of dielectric material spaced from the latter for movably supporting a product to be treated in the discharge region of said electrode means, conductive means coaxial with and within each roller, and capacity-forming means completing said circuit from said conductive means to said source.

10. In electrical treating apparatus, in combination; an electric discharge circuit comprising a source of suitable potential, electrode means, rollers of dielectric material spaced from the lat- -ter for movable supporting a product to be treated continuous along the path of movement, means spaced from said electrode means for transporting aproduct to be treated into the discharge region of said electrode means, and means forming a condenser capable of withstanding the potential of said source without breakdown for causing local rupture in said discharge region.

12. A treating apparatus like that of claim 11 in which the transporting means includes a cylindrical product-carrying member of solid dielectric material which is included in said discharge circuit for receiving the discharge from said electrode means.

13. A treating apparatus like that-of claim 11 in which the transporting means is made of solid dielectric, such as glass, which is included in said discharge circuit and which moves with the product.

14. A treating apparatus like that of claim 11 in which the transporting means comprises a plurality of rollers and the electrode means comprises a rotating toroidal electrode whose axis is substantially in line with the direction of travel of the product.

15. A treating apparatus like that of claim 11 in which the electrode means comprises a rotating toroidal electrode whose plane of rotation is inclined to the direction oftravel of the product.

16. A treating apparatus like that of claim- 11 in which the electrode means comprises a drum like support rotating about a generally horizontal axis, and electrode means substantially ring-like carried by said drum.

17. An apparatus like that of claim 16 in which the electrode means comprises a drum-like support rotating about a generally horizontal axis and in which the electrode means is substantially ring-like and is detachably mounted on the drum.

18. Anapparatus like that of claim 11 in which the electrode means comprises a drum-like rotatable support carrying an electrode, and in which the said electrode is toroidal and thedrum is provided with means for detachably holding the electrode. 19. A supporting structure having extending laterallytherefrom a sleeve, a stator carried by said sleeve, an annular rotor extending about said stator, a rotor support for said rotor and having means rotatably supporting it coaxially with said sleeve, and electrode means carried by said rotor support.

20. An electrode and driving structure like that of claim 19 in which the rotor support is in the form of a housing completely enclosing the stator,

rotor, and their respective, supports.

21. An electrode and driving structure like that of claim 19 in which the means, that rotatably supports the rotor support is accommodated within said sleeve.

22. An electrode and driving structure like that of claim 19 in which an electrically conductive connection between the supporting structure 'and the rotor support is maintained by brush therebetween, and means for positioning a prodnot to be treated'in the space between said electrode means, the surface of one of said. electrode means being conductive and the surface of the other being non-conductive. 24. In electrical treating apparatus, in cpmbi nation, an electric discharge circuit comprising a source of suitable potential, spaced electrode means having curved effective surfaces of radii of curvatures proportioned to the spacing therebetween to achieve approximation of equality between maximum and average voltage gradients therebetween, means for positioning aproduct to be treated in the space between said electrode means, one of said electrode means being in the form substantially of a cylinder and having a non-conductive surface.

25. In electrical treating apparatus, in combination, an electric discharge circuit comprising a source of suitable potential, spaced electrode means having curved efiective surfaces of radii of curvatures proportioned to the spacing therebetween to achieve approximation of equality between maximum and average voltage gradients therebetween, means for positioning a product to be treated in the space between said electrode means, one of said electrode means having a non-conductive surface and the other being in the form of a toroid, and means for rotating the toroidal electrode means at high speed.

\ 26. In electrical treating apparatus, in combi nation, an electric discharge circuit comprising I a source of suitable potential, spaced electrode means having curved effective surfaces of radii of curvatures proportioned to the spacing therebetween to achieve approximation of equality between maximum and average voltage gradients therebetween, means for positioning a product to be treated in the space between said electrode means, one of said electrode means having a non-conductive surface, and means for movin the eifective surface of one of said electrode means.

2'7. In electrlcal treating apparatus, in combination, an electric discharge circuit comprising a source of suitable potential, spaced electrode means having curved effective surfaces of radii of curvatures proportioned to the spacing therebetween to achieve approximation of equality between maximum and average voltage gradients therebetween, one of said electrode means being in the form of a roller member and having a non-conductive surface, and means for rotating said roller member to cause it to carry a product to be treated into'the space between said electrode means.

28. In electrical treating apparatus, in combination, an electric discharge circuit comprising a source of suitable potential, spaced electrode means between which electric discharge takes place, means for supporting a productto be treated in the discharge region between said electrode means, one of said electrode means having a smooth surface substantially continuous along the path of movementv and means for giving the smooth surface of said one electrode means a high velocity of movement.

29. In electrical treating apparatus, in combination, an electric discharge circuit comprising a source of suitable potential, spaced electrode means between which electric discharge takes place, means for supporting a product to be treated in the discharge region between said electrode means, one of said electrode means being rotatable and having an eifective surface substantially free from protrusions with all points thereon in a given plane normal to the axis of rotation lying along a substantially unbroken circumference whose center is substantially coincident with the axis of rotation, and means for electrodes are thereby adapted to serve rotating said rotatable electrode means at high peripheral velocity.

30. In electrical treating apparatus, in combination, means for moving a product to be treated along a given path, electrical means spaced from said path and comprising a plurality of rotatable electrode members, means supporting said electrode members for rotation about axes in planes parallel to the said path and with the electrode members extending generally transversely of said path, each electrode member having an effective discharge surface which is continuous alonga circumference thereof lying in a plane at right angles to the axis of rotation thereof, and means including a source of suitable potential connected to said electrode means for effecting discharge through the product moving along said path.

31. An electrical treating apparatus as claimed in claim 30 in which means are provided for rotating certain of the said electrode members in one direction and others in reversed direction.

32. An electrical discharge apparatus as claimed in claim 30 in which the electrode members have individually related thereto motive driving means therefor, the motive driving means of certain of said electrode members rotating them in one direction and the motive driving means of others driving them in reversed direction.

33. A double electrode structure for treating apparatus comprising, in combination, two substantially identical units each comprising a supporting arm to one side of which is rotatably supported an electrode member with driving motive means therefor, and means for securing said two arms together with the other sides thereof face to face.

34. An electrode structure as claimed in claim 33 in which the driving motive means for the two units are, constructed to rotate normally in v the same direction whereby, when said two units are secured together with the arms thereof face to face, one of said motive means is reversed end for end with respect to the other and the two driven in opposite directions.

35. In an electrical treating apparatus, the

combination of a discharge electrode above a treating zone and a plurality of conveyor rollers beneath said treatment zone, at least one of which is in the electrical circuit of the discharge and is as a discharge electrode to cooperate :with the discharge electrode above the treatment zone for establishing a discharge therebetween. V

36. In an electrical treating apparatus, the combination of a discharge electrode above a treatment zone and a plurality of conveyor rollers beneath said treatment zone, at least one of said rollers having a conductive portion in the electrical circuit of the discharge and a solid dielectric means associated with the conductive means at the surface of the roller to form a capacity in series with the discharge and being adapted to serve as a discharge electrode to cooperate with the discharge electrode above the treatment zone for establishing a discharge therebetween.

3'7. In an electrical treating apparatus, the combination of a discharge electrode above a treatment zone and a plurality of rollers mounted beneath said treatment zone adapted movably to support material to be treated thereinand at least one having a dielectric surface and conductive means within the dielectric surface whereby said roller is adapted to serve as a capacitative electrode to cooperate with the discharge electrode above the treatment zone, and an energizing circuit including the electrode above the treatment zone and the conductive means within the roller for establishing and maintaining a discharge.

38. In an electrical treating apparatus, the combination of a discharge electrode above a treatment zone and a plurality of conveyor rollers beneath said treatment zone at least one of which comprises a dielectric tube with conductive means therein, a conductive pivot at one end electrically connected to said conductive means, and support means in the discharge circuit electrically connected to said conductive pivot by an oilless conductive bearing.

39. In an electrical treating apparatus, a conveyor roll adapted to serve also as a capacitative electrode which comprises a tube of dielectric material, conductive means within said tube, and at least one conductive pivot electrically connected to the conductive means within the tube.

40. In an electrical treating apparatus, spaced electrodes for a discharge one of which is movable and has a surface which is convex at the discharge area thereof and substantially continuous along the path of travel, and means for moving the surface of the electrode without changing its effective shape within the discharge area.

41. In an electrical treating apparatus, spaced electrodes for a discharge, one of said electrodes having a discharge surface which is substantially circular and mounted with its axis transverse to the direction of the discharge therefrom, and means for rotating said electrode about its axis.

42. In an electrical treating apparatus in which a product to be treated is subjected to a discharge resulting from impressing a high potential across two sets of electrode elements, the combination of, a tubular roller of dielectric material, a conductor within said roller, and an elongated condenser element electrically connected with said conductor and mechanically connected to one end of said roller.

43. In electrical treating apparaus, the combination of, a tubular roller of dielectric material, means to drive said roller, and a conductor element positioned in said roller, said means to drive said rollers including a belt of dielectric material.

44. In electrical treating apparatus, the combination of, a plurality of electrode rollers and a toroidal electrode structure positioned in operative relationship with respect to said plurality of electrode rollers, each of said electrode rollers having an individual electrode element associated therewith and. cooperating with said toroidal electrode structure.

45. In electrical apparatus in which a product to be treated is subjected to a discharge resulting from impressing a high potential across a pair of electrode structures, an electrode structure comprising a plurality of electrode units,

each of said units having an elongated shell of dielectric material and an elongated electrode' means and an electrical conducting means, said conducting means having a portion adjacent the treatment zone but separated therefrom byan insulating means of solid dielectric material'and having another portion extending to a point remote from said treatment zone and electrically connected to said condenser means.

47. In electrical apparatus in which a product to be treated is subjected to a discharge resulting from impressing a high potential across a pair of electrode structures, an electrode structure comprising a plurality of elongated electrode-roller units positioned in parallel relationship and in a plane parallel to the plane of movecluding an elongated element which is provided with dielectric shields, and the-other of said condenser structures comprising a single flat metallic plate.

49. In electrical treating apparatus, a con- 5 denser construction composed of a pair of condenser structures positioned in cooperating re-. lationship, one-of said condenser structures comprising a plurality of elongated condenser elements, each of said elements having static shields 10 at its ends and a socket which is adapted to provide a pivot support.

50. In electrical treating apparatus, means to support a product being treated including, a con-' ment of the material being treated, each of said veyor roller adapted to serve as a capacitative 15 electrode-roller units having an electrical conelectrode formed by a tube of dielectric material ducting means and an insulating means of solid having conductive means therein and having a dielectric material covering said electrical conconductive pivot electrically connected to the ducting means. conductive means within'said tube, a condenser 48. In electrical treating apparatus, a conelement supporting said pivot and electrically 20 denser construction composed of a pair of condenser structures positioned in cooperating relationship, one of said condenser structures in-' connected therewith, andsa dielectric means supporting said condenser element.

FRANKLIN S. SMI'I'H.

CERTIFICATE OF CORRECTION. Patent Noa 2,152,707,. October 11, 1958.

FRANKLIN s..- SMITH.

It is hereby certified that error appears in the printed specification of the above mnnbered patent requiring correction as follows Page 12, first column, line 51, claim 17-, for the claim reference numeral '16." read 11; page 15, first column, line 1 8, claim 35, for the word "treating" read treatment; arid that the said Letters Patent should beread' with this correotion thereinthatthe same may confior'm to the record of the case in the Patent Office; p

si ed and sealed this an day of January, A.D.' 1959,

Henry Van arsdale 1) Acting Commissioner of Patients. 

